BRPI0717991A2 - MICROUSINATED ELECTROLYTE BOARD, CELL-TO-FUEL DEVICES USING THE SAME, AND MICROUSINATION METHOD FOR PRODUCTION OF CELL-TO-FUEL DEVICES. - Google Patents

Description

DETAILED DESCRIPTION REPORT FOR "MICROUSINATED ELECTROLYTE BOARD, CELL TO FUEL DEVICES USING THE SAME, AND MICROU SIGNING METHOD FOR PRODUCTION OF CELL TO FUEL DEVICES".

Background of the Invention

Field of the Invention

The present invention relates generally to ceramic electrolytes and fuel cell devices using them, and to laser micromachining of electrolyte plates and multi-cell solid oxide fuel cells.

Technical Background

The present invention relates to particles formed by laser processing of solid oxide based fuel cell electrolyte plates, as well as the manufacture of electrolyte supported solid oxide fuel cells and fuel cell devices.

Solid oxide-based fuel cell devices incorporating flexible ceramic electrolyte plates are known. In such fuel cell devices, generally one or more electrolyte plates are supported within a housing, over a frame, or between a pair of mounting assemblies, which may be a frame or a distributor block. Electrolyte plates can be used in a multi-cell or single-cell design.

One common approach utilizes a fuel cell device consisting of a single cell design, wherein the thickest component of the fuel cell is an anode layer. This anode layer acts as both a support and a catalyst and may be 100 to 1000 microns thick and is generally formed of an yttria stabilized nickel and zirconia compound. Such single cells also include a thin electrolyte layer overlaying the anode layer, and a cathode layer overlaying the electrolyte.

In a multi-cell design, such as that disclosed in US Patent 6,622,881 to Corning Incorporated, the fuel cell device includes an electrolyte plate in the form of a thin ceramic plate (e.g., zirconia treated with oxide). Yttrium (Y 2 O 3)). The zirconia-based electrolyte plate can be 20 to 30 microns thick. Generally, the treated zirconia-based electrolyte plate supports several cells, each of which is formed by an anode and cathode layer on either side of the treated zirconia plate. The pre-sintered thin electrolyte plate can support a single anode and cathode pair, thus forming a single cell device, or multiple anodes and cathodes, and multiple cells are fabricated on a common electrolyte substrate and are interconnected across the plate thickness. electrolyte by the conductor via connectors (pathways).

In order to avoid rupture of the electrolyte plates, the fuel cell device manufacturing process generally utilizes mechanical drilling of the through holes and mechanical cutting of the device edges while the electrolyte plate is in the unburned state. The process of mechanically drilling unburned ceramic electrolyte plates requires predicting sintering shrinkage of a particular batch of electrolytes under specific furnace conditions. If forecasting is disabled, drilled through holes will be misaligned after sintering. After drilling and cutting, the electrolyte is burned and generally undergoes a linear shrinkage of 15% to 30% due to the decoupling and sintering process. Larger electrolyte parts require better accuracy of shrinkage values to maintain the tolerances required for device manufacturing, especially with multi-cell devices. For example, an electrolyte with a length of 50 cm and bore positioning tolerances of +/- 200 μηι in the sintered state is expected to shrink the electrolyte by more than 0.05%. The drilling and mechanical cutting of unburned electrolyte imposes limitations on the speed of fabrication, the size of the details, and the quality of the creases and folds produced. In addition, machining parts in the unburned state requires precise prediction of part shrinkage to maintain dimensional tolerances. Such prediction is very difficult to perform with the desired accuracy and requires real devices to be sacrificed for testing.

The general use of 5 thick ceramic laser micro machining is known. It is applicable to the machining of large ceramic tiles with thicknesses of 250 μηι or more, and not thin electrolyte films of thickness less than 50 μηι. Thin zirconia-based sintered electrolyte plates (less than 50 μηι) are brittle when they are cut and / or perforated by mechanical means due to crack formation.

The process of forming through holes in sintered ceramic substrates for electronic components is described in US Patent 6,270,601. The present invention discloses the use of mechanical or laser drilling of thick sintered ceramic substrates with thicknesses from 3 to 60 thousandths of an inch (76.2 to 1524 μηι). The present reference suggests that laser drilling of sintered ceramic parts can be achieved by using both CO2 and excimer laser systems. No details are given on how to laser drill through holes in sintered electrolyte plates. The holders tried to use CO2 laser to drill thin zirconia-based ceramic electrolyte plates, but were unsuccessful due to the large number of cracks created by thermal effects. US Patent 6,270,601 also gave no guidance on how to use the excimer laser to properly cut or puncture electrolyte plates.

US Patent Publication No. 2002/0012825 describes a fuel cell electrolyte plate with three dimensional micro-details on its surface. This application does not teach or suggest that electrolyte plates can be laser-machined after sintering.

Previous attempts to produce flat electrolytes thicker than 50 μηι have resulted in dimples or dimples and burrs at the edges as described in European Patent EP 1063212B1. This reference reveals the stacking of electrolyte plates during sintering to limit the height of undulations and burrs to less than 100 μηι. The reference teaches that zirconia plates and other ceramic plates are brittle when subjected to external forces in a bending direction. In contrast, fuel cells formed of thin flexible electrolyte can withstand significant curvature without failure. However, they can also develop edge undulations when sintered, and edge undulation can produce stress, and fracture the plate when the undulation is flattened.

Summary of the Invention

The present invention utilizes laser micro-machining of sintered electrolyte plates and fuel cell devices to cut electrolyte plates and / or device components to size or trim the edges of sintered electrolyte plate or fuel cell devices. , and / or produce through holes and surface modifications or patterns.

According to an aspect of the present invention, a sintered electrolyte plate comprises: a body whose thickness is no more than 45 μπι, and micro-machined details having at least one edge surface having at least 10% ablation. According to one embodiment, this edge surface has more than 50% fracture and less than 50% ablation.

According to one embodiment of the present invention, the method of micro machining an electrolyte plate comprises: (i) supporting a sintered electrolyte plate; (ii) microplating the electrolyte plate with a laser, wherein said laser has a wavelength of less than 2 μηι, a fluency of less than 200 Joules / cm2, and a repetition rate (RR) of between 30 Hz and 200 KHz. . Preferably the cutting speed is greater than mm / sec. Preferably, the laser wavelength is less than 400 nm, the repetition rate (RR) is between 30 KHz and 200 KHz. In some embodiments, the laser creep is less than 30 Joules / cm. According to some embodiments, the laser micro-machining process combines ablation and self-cleavage into one occurrence and increases cutting speed capability. According to some embodiments, the laser is an n laser (pulse duration <1 μ8, for example, from 1 to 100 ns). According to some embodiments, this laser is a 355 nm laser.

The disclosed method is applicable to the fabrication of details formed by laser micro-machining of electrolyte supported multi-cell fuel cell devices, and is applicable to microfracture of flexible electrolyte supported SOFC devices. As mentioned above, said method is applicable to the cutting, shaping and drilling of solid oxide-based fuel cell electrolytes less than 45 μηι in thickness and enables new designs and manufacturing processes of fuel cell devices.

An advantage of the present invention is that it advantageously enables the manufacture of new fuel cell designs, and / or advantageously increases the manufacturing throughput and strength of current fuel cell devices. More specifically, the speed, placement accuracy, and quality resulting from the electrolyte plate edge (s) allows for flexibility in device design, handling, and improved resistance of the electrolyte plate edges. Preferably, the surface roughness of the laser micro-machined regions is less than 0.5 Dm RMS, more preferably less than 0.4 Dm RMS. Preferably, this surface has peak-to-valley roughness of less than 5.5 Dm, or Ra surface roughness of less than 0.3 Dm. Fuel cell devices can also be drilled, cut or micro-machined at various times during the manufacturing process, resulting in unique fuel cell devices such as complex perimeter shapes or through-hole, electrode or other patterns. layers to the edge of the electrolyte, and 5 thin regions of the electrolyte less than 5 Dm thick. This micromachining process can be used at any time desired after electrolyte sintering, allowing flexibility in device manufacturing. The resulting method advantageously results in electrolyte devices and plates having surprising improvements in the flatness and strength.

According to one embodiment of the present invention, laser machining of single cell and multiple cell devices may be performed after sealing or mounting the fuel cell device (s) in a support or distribution structure, and results in better: electrolyte plate edge strength, device flatness, edge quality, minor and minor creases, minimization of electrolyte plate edge curl, and yield and production time. According to another embodiment, micro-machining may also be performed to cut electrolyte plates, where multiple fuel cell devices are drawn in pattern (for example, printed) on a single electrolyte plate and the electrolyte plates are then optionally. laser machined to produce multiple devices, thus saving time and labor. The laser micro-machining method advantageously allows micro-machining of the electrolyte in the sintered state rather than before firing. This eliminates the need to accurately predict shrinkage during binder burning and sintering. In addition, it also eliminates the need for such shrinkage to be uniform throughout the entire electrolyte plate.

Brief Description of Drawings:

Figure 1A illustrates zirconia absorption as a function of wavelength.

Figure IB schematically illustrates the process of grooving an electrolyte plate with a laser beam.

Figure IC illustrates a through hole in accordance with one embodiment of the present invention.

Figures 2a and 2b are sectional views

cross-section of examples of through-holes obtained with laser micro-machining. Figure 2a illustrates a through hole drilled through an electrolyte plate. Figure 2b illustrates an exemplary through hole drilled through the electrolyte plate and an anode.

Figure 3 schematically illustrates the use of laser micro-machining to cut multiple fuel cell devices fabricated on a common electrolyte plate substrate.

Figure 4 schematically illustrates a view

cross-section of a fuel cell device with anode (s) and cathode (s) located less than 5 mm from the edge of the electrolyte plate.

Figure 5 illustrates a laser cutting system in accordance with one embodiment of the present invention.

Figures 6a and 6b are photographs of a hole

laser micro-machined passageway on a sintered electrolyte plate. Figure 6a is a photograph of the upper surface of the sintered electrolyte plate (i.e., the surface on which the laser beam has focused) and Figure 6b is a photograph of the lower surface of the sintered electrolyte plate (i.e. the surface from which the laser beam exited).

Figures 7a and 7b are SEM photos of laser microplated edges on the sintered electrolyte plate. Figure 7a is a top view (surface on which the laser focused) and Figure 7b is a cross-sectional view of the micro-edge edge face.

Figure 8 illustrates another cutting system to

laser.

Figures 9a to 9c are SEM images of a laser cut edge of an exemplary sintered electrolyte plate. Figure 9a illustrates a cross-sectional view of a laser cut edge. Figure 9b illustrates the edge profile of a laser cut edge (away from the image). Figure 9c is similar to Figure 9a, but shows a larger magnification of a laser cut edge cross section. It also illustrates the effects of individual laser pulses on the upper ablation region.

Figures 10a to 10c are graphical representations of the surface roughness of the edges of the electrolyte plate micro-machined by an ns laser.

Figures 1a to 2c are graphical representations of the surface roughness of the edges of the electrolyte plate micro-fined by an fs laser.

Figures 12a and 12b are XPS line profiles showing the change in relative concentrations of yttrium and zirconium. Figure 12a is a line scan starting at the sintered and mechanically cut edge. Figure 12b is a line scan starting at an edge of a laser micro-sintered sintered electrolyte plate.

Figures 13a to 13c are SEM images of a

laser cut edge of an exemplary sintered electrolyte plate. Figure 13a illustrates a cross-sectional view of a laser cut edge. Figure 13b is similar to Figure 13a, but shows a larger magnification of a laser cut edge cross-section 20. It also illustrates the effects of individual laser pulses on the upper ablation region. Figure 13c illustrates the edge profile of a laser cut edge (away from the image).

Figures 14a and 14b are XPS line profiles showing the change in relative concentrations of yttrium and zirconium. Figure 14b is a line scan starting at a laser micro-sintered sintered electrolyte plate edge. Figure 14b is a line scan starting at the sintered and mechanically cut edge.

Figures 15a-15c are SEM images of a laser cut edge of an exemplary sintered electrolyte plate. Figure 15a illustrates a cross-sectional view of a laser cut edge. Figure 15b is similar to Figure 15a, but shows a larger magnification of a laser cut edge cross section. Figure 15c illustrates the edge profile of a laser cut edge (away from the image).

Figures 16a-16c are SEM images of a laser cut edge of an exemplary sintered electrolyte plate. Figure 16a illustrates a cross-sectional view of a laser cut edge. Figure 16b is similar to Figure 16a, but shows a larger magnification of a laser cut edge cross section. It also illustrates the effects of individual laser pulses on the upper ablation region. Figure 16b illustrates the edge profile of a laser cut edge (away from the image).

Figure 17 shows probability plots

of edge resistance showing Weibull distributions for laser-cut and mechanically cut electrolyte samples measured by 2-point curvature.

Figures 18a to 18c are optical microscope images of exemplary through holes drilled through sintered electrolyte plates. Figure 19 illustrates laser pulse patterns used in a multipass drilling method.

Figures 20a and 20b are photographs of an exemplary laser micro-machined through hole in a sintered electrolyte plate. Figure 20a is a photograph of the upper surface of the sintered electrolyte plate (i.e., the surface on which the laser beam has focused) and Figure 20b is a photograph of the cross-sectional surface of the sintered electrolyte plate. Figures 21a to 21f are photographs of other

Example laser micro-machined through holes in a sintered electrolyte plate. Figures 21a, b and c are photographs of the upper surfaces of the sintered electrolyte plate (i.e., the surface on which the laser beam 15 has focused), and Figures 21b, d, f are photographs of the cross-sectional surface of the electrolyte plate. sintered.

Figure 22 shows edge contour plots (top) of the electrolyte plate after sintering and mechanical cutting, and (bottom) after removing 2 mm from the edge with laser micro-machining.

Figures 23a and 23b are SEM images of a 60 μηι microplated hole with a femtosecond laser in a sintered electrolyte plate. Figure 23a is a photograph of the upper side (where the laser falls) and Figure 23b is a photograph of the lower side (laser beam output). Figures 24a and 24b are SEM images of the edges of sintered zirconia-based electrolyte plates. Figure 24a illustrates an electrolyte plate edge surface that was mechanically cut (in the raw state) prior to sintering. Figure 24b illustrates the laser cut sintered (micro-machined) edge. The length of the scale bar is 10 μηι.

Figure 25 shows resistance probability graphs showing Weibull distributions for laser-cut and mechanically cut electrolyte electrolytes, measured by 2-point curvature.

Figures 26a-26c schematically illustrate laser micromachining of the electrolyte surface. Figure 26a illustrates a single electrode layer electrolyte plate, Figure 26b illustrates a laser micro-machined detail, Figure 26c illustrates a fuel cell device with a second electrode situated over the micro-machined detail (window).

Figures 27a to 27d are photographs of exemplary laser micro-sintered sintered electrolyte surfaces.

Detailed Technical Description of the Invention:

According to some embodiments, a laser micromachining method of fuel cell electrolyte plates 100 and fuel cell devices 150 includes the steps of: (i) supporting a sintered electrolyte plate or fuel cell device; (ii) microplating the electrolyte plate or fuel cell device with a laser 160 at a cutting speed of more than 20 mm / sec, preferably more than 30 mm / sec, and more preferably more than 35 mm / sec. Mon; wherein said laser 160 has a wavelength of less than 2 μηι; optical power of more than 2W, and / or laser fluency of less than 3 Joules / cm2; and repetition rate (RR) between 30 Hz and I MHz. Preferably, the laser wavelength is less than 400 nm, and even more preferably less than 300 nm, and the repetition rate (RR) is between 30 KHz and 200 KHz. In some embodiments, the laser creep is less than 400 Joules / cm, for example 350 Joules / cm or less, or even less than 26 Joules / cm2. In some embodiments, the laser wavelength is 355 nm, in other embodiments, the laser wavelength is in the range 200 nm to 300 nm.

This method can be successfully applied to flexible ceramic electrolyte plates with a thickness of 45 μηι 20 or less and advantageously does not produce significant microfissure on or adjacent to the micro-milled surfaces. For example, this method may be used with thin sintered ceramic electrolyte plates 100 (e.g. zirconia-based electrolyte plates) to produce through-holes 25 102, cut edges 103, and surface patterns 105 (e.g. microwindows). According to some embodiments (described below), this method results in electrolyte plate 100 with laser machined details 102, 103, 105 having at least one edge surface 104 with at least 10% ablation (HO region). According to at least one embodiment, said edge surface has more than 50% fracture (region 112) and less than 50% ablation. According to some embodiments, the surface roughness of the surface of the laser micro-machined edge 104 is less than 0.5 □ m RMS, more preferably less than 0.4 Dm RMS. Preferably, edge surface 104 exhibits peak-valley roughness less than 5.5 Dm, or Ra surface roughness less than 0.3 Dm. According to some embodiments, the peak valley trough surface roughness of the electrolyte plate in a laser micro-machined edge surface region (edge) is 15 0.2 to 5.5 Dm, preferably 1 to 5 Dm, more preferably less than 4 Dm. According to some embodiments, the laser micro-machined surface 104 has an average crystal bead size smaller than I Dm. According to some embodiments, the fractured surface region 112 has a smaller average crystal granule size 20 than that of the crystals in the transition zone 114 between the fracture region and the ablation region.

Laser induced rupture and / or laser ablation micromachining utilizes high intensity laser pulses provided by a laser 160 to selectively remove material. Laser micromachining can be done, for example, with long pulse UV lasers, ultra short pulse lasers such as peak-second lasers and femtosecond lasers. For example, we can use peak-second lasers, such as NdiYVO4 lasers with a mode synchronizing seed and power amplifiers, or femtosecond lasers, such as the Ti: Sapphire laser with a regenerative amplifier system; as well as ultra-fast fiber lasers (ie with pulse duration <100 os). Nanosecond nanosecond DPSS (Laser Diode Pumped Solid State) lasers, such as the 3rd harmonic (355 nm) and 4th (266 nm) of Nd: YAG and Nd: YV04 lasers , are also well suited to the laser micromachining method according to embodiments of the present invention.

Figure 1a illustrates the relative optical absorption of zirconia-based electrolyte plates as a function of laser wavelength. Optical absorption of zirconia is characterized by relatively low absorption at visible wavelengths and significant dispersion due to the multi-crystal granular nature of the material. Laser micromachining with nanosecond (<400 nm) or deep UV (<300 nm) lasers has the advantage of producing a small or insignificant heat-affected region and smaller detail than those obtained using visible and infrared lasers. . The UV or deep UV laser photons are absorbed by the desired material and have sufficient energy to directly decompose the material. Deep UV and UV laser light can be reduced in focus to smaller limited diffraction sizes and can machine smaller details than visible and infrared laser light.

Laser micromachining with ultra-short pulse (<100 ps) lasers can also produce small details with limited (ie small) or no heat-affected zone, although the underlying principle of micromachining operation is fundamentally different. Since ultra-short pulse laser micromachining is based on nonlinear light absorption in the material, the target material need not directly absorb the laser light. Instead, the electric field in an ultrashort pulse laser is so extreme that the initial free electrons in the target material are accelerating to create a cascade of free electrons through collisions. The cascade of free electrons results in the decomposition of the target material. Since ultra-short laser machining is based on nonlinear absorption, it is not limited to diffraction. Details as small as tens of nanometers were machined using this method.

Typical techniques used in through-hole drilling / laser cutting applications (i.e., 20 laser micro-machining) according to some embodiments are percussion drilling, trepanning, and helical drilling. In percussion drilling, the laser focal point is fixed and a series of laser pulses is used to ablate the material. Trepanning is used to make larger holes, and is essentially a percussion drilling process along a circular path. Unlike trepanning, the helical perforation reaches its penetration only after many turns of the spiral describing the trajectory of the ablation front. Helical drilling (laser cutting) is not limited to circular geometry. Holes 5 of any shape may be formed by the use of a sweeping device or stages of translation.

Cutting, roughing the edges or drilling the holes / cutting of the electrolyte plate or fuel cell devices by laser micro-machining can be accomplished either by complete ablation of the target material (eg with a femtosecond laser) or by incision. (via ablation) and fracture of the target material (eg with a 266 or 355 nanosecond laser). This is illustrated schematically in Figure 1B. Fracture through the thickness of the electrolyte plate occurs as a result of autocleavage (autofracting) due to the thermal stress across the depth of the electrolyte material. When laser micromachining (from electrolyte plates or fuel cell devices) utilizes fracture of the target material via self-cleavage (so that> 50% of thickness is fractured), this process results in laser cutting speeds of about 30 mm / sec. Drilling small diameter holes can be performed using ablation using high velocities (faster than 30 mm / sec) and low pulse energies (eg below 60 μ, or below 50 μΐ, 40 μΐ, 3 μJ, 20 μΙ, 17 μJ or 15 μΐ) to minimize the formation of micro cracks around the perimeter of the hole. (See Figure 1C) If laser micro-machining of zirconia-based electrolyte plates was performed largely through ablation (eg, ablation of 90% to 100% of target material), according to some embodiments, the Electrolyte plate 100 has 5 granular growth of less than 2 Dm on the cut surface (subjected to ablation). That is, the granule size on or immediately adjacent to the ablation surface is larger than the granule size in another area (non-ablation area) of the electrolyte plate. For example, a typical granule size on a non-ablation surface may be 0.2 to 0.5 μηι, while the ablation surface may have larger granule sizes (eg 0.9 μηι , 1 μηι, 1,3 μηι, 1,5 μηι or 2 μηι).

An advantage of the method of the present invention is that this method: (i) advantageously enables the manufacture of new fuel cell designs such as complex non-rectangular electrolyte shapes and through-hole patterns, complex non-circular through-hole shapes , smaller micro-finely thin electrolyte regions less than 5 Om thick; and / or (ii) advantageously increases the throughput and strength of current fuel cell devices. More specifically, the speed, placement accuracy, and resulting quality of the electrolyte edge give flexibility to device design, handling, and resistance to the edge (s). The laser micromachining process of the invention can be used at any desired time after sintering of the electrolyte, allowing flexibility in device manufacturing. A typical fuel cell device 150 includes at least one electrolyte plate 100 and preferably a plurality of electrode pairs 152 (cathodes and anodes), electrical connectors (e.g., conductive pathways located within the through holes). ), conductive bars, and other optional layers. Fuel cell devices 150 may also be advantageously drilled, cut or micro-machined at various times during the manufacturing process, resulting in fuel cell devices with unique attributes such as shape, flatness and strength. The resulting method advantageously results in fuel cell devices and electrolyte plates having surprising improvements in the flatness and strength (e.g., peak-valley flatness less than 50 Dm and bending strength greater than 2 GPa). For example, in accordance with one embodiment of the present invention, laser machining of single cell and multiple cell solid oxide based fuel cell devices may be performed after sealing or mounting of the device (s). fuel cell in a support or distribution structure, which results in improved edge strength, edge quality, handling and yield and production speed. According to another embodiment, several fuel cell devices are printed on one electrolyte plate, and the electrolyte plates are then cut (laser micro-machined) to separate the fuel devices from each other, thereby simultaneously producing multiple devices. , thereby saving time and labor, and increasing production speed.

During the laser micro-machining process,

or the electrolyte plate 100 (or fuel cell device 150) can be moved mechanically, or the laser beam provided by laser 160 can be swept through the electrolyte plate (or fuel cell device) to expedite ίο the processing. In addition, the output of a laser can be split into multiple micromachining laser beams to speed up engraving time. Some embodiments of the present invention have better electrolyte plate edge strength (flexural strength) greater than 1.8 GPa. Some embodiments of the present invention have better electrolyte plate edge strength (flexural strength) greater than 1.8 GPa. 2 GPa. This resistance is measured in a 2-point bend system, where the 2 cm x 8 cm laser microplate electrolyte plate sample is bent over itself between the approaching parallel plates 20 until it breaks in two. sections approximately 2 cm by 4 cm.

Improved Edges: Mechanical cutting and drilling require careful attention to maintaining the cutting tool to avoid lacerating the edges of the electrolyte. Laser micro-machining of machined ceramic electrolyte plates 100 according to embodiments of the present invention is advantageously capable of producing a cutting edge with an edge surface 104 with less roughness, splinters, tears or other stress concentration aspects of the that an edge produced by mechanical cutting. This improves the strength of the edge of the electrolyte plate, and may advantageously reduce the number of damaged electrolyte parts during fabrication due to breakage at the edges.

As the size of the electrolyte plate increases, it experiences greater stresses during the manipulation and sintering cycles. Laser micro-machined fuel cell devices 150 and electrolyte plates 100 with higher edge strength will result in reduced breakage rate of electrolyte plates during manufacture.

Better Fabricability and Quality: Laser cutting of device substrates (electrolyte plates of the desired size) from an oversized sintered electrolyte plate allows the oversized electrolyte plate to be positioned using only common mechanical alignment. Since drilling of through holes and cutting edges of a sintered electrolyte plate can occur during the same step, precise alignment to a preformed edge is not required. In this case, the oversized electrolyte plate is placed in the translation stage (eg, stage XY or stage XYZ) so that an almost perfect area is selected by laser cutting (micro-machining) for device manufacture. The ability to adjust the position of fabricated fuel cell devices makes it possible to avoid electrolyte plate defects 101. The precise location of the cut electrolyte plate part can be adjusted within the oversized electrolyte plate to avoid identified defects. This improves overall device quality and process throughput.

Laser micro-machining can also be used to cut the sintered electrolyte to the correct shape (rectangular, circular or other) and to the correct size. Generally, the electrolyte plate is mechanically cut in the unburned state and then sintered. Thus, the shrinkage that will occur during sintering needs to be predicted precisely, which is difficult to do. Laser micromachining of sintered electrolyte plates does not require precise positioning.

For example, 10-cell 150 devices

Manufactured with overall dimensions of 12 cm x 15 cm may have narrow tolerances, for example +/- 1 mm to fit the mounting frame. Using laser micro-machining to cut the electrolyte plate 100 to the correct size 20 eliminates the need for precise shrinkage control during sintering. In addition, laser micro-machining can occur at absolute times during the manufacturing process. For example, the electrolyte plate 100 may be cut before, after or between the separate print / burn steps of the electrode material. If the electrolyte plate is mechanically cut to the correct size and perforated while attached to the Teflon backing film for manipulation purposes, mechanical cutting and drilling will damage the backing film and make recycling 5 impracticable. Since laser micro-machining occurs when the electrolyte plate is in the burned state, the electrolyte support film (eg Teflon support) can now be recycled continuously.

Complex configurations: Laser micromachining enables the manufacture of new fuel cell device designs that are not possible or feasible through mechanical cutting. For example, the electrolyte plates 100 may be laser cut to complex non-rectangular shapes, any desired patterns, and the edges may be cut in extremely close proximity to the previously printed layers. To achieve this by mechanically cutting raw (ie, non-synthesized) electrolyte plates, it would be necessary to accurately predict shrinkage of parts during sintering, which is difficult or impossible to achieve in manufacturing (on a commercial scale).

Laser micro-machining does not require rigid back support such as mechanical cutting, and various lens systems or an autofocus process can be incorporated into the configuration. This allows drilling of through holes and cutting edges to occur on electrolyte plates with absolute surface profiles, contours and corrugations that would otherwise have been difficult or impossible with mechanical means. More specifically, the laser beam depth and shape can be modified to cut corrugated structures with large surface contours or to produce molded edge profiles. Electrolyte plate corrugations are useful for improving the deformation tolerance of the device as described in U.S. Patent 6,582,845B2, but are difficult or impossible to accurately cut or puncture in the raw, unburnt state. The laser micromachining process of the present invention allows cutting and drilling of holes in the corrugated pre-burned electrolyte with height variations greater than 100 μηι, 250 μιη or even 1000 μηι or more, which may be useful for strain relief.

Improved ways: Laser micromachining

allows efficient production of high quality through holes 102 with diameters smaller than 75 μηι (eg 60 μιη, 45 μιη, 40 μηι, 30 μηι, 25 μηι, or 20 μηι), punching / cutting through printed electrodes or another 20 layers, complex non-circular passageways, and complex passageway patterns.

According to some embodiments, the laser micro-machining process may be used to produce through-holes 102 in the sintered electrolyte plate 100, rather than mechanical drilling in the unburned state. The process of mechanically drilling the unburned ceramics requires providing for sintering shrinkage of a particular batch of electrolytes under specific furnace conditions. If forecasting is disabled, drilled through holes will be misaligned after sintering. The shrinkage of the electrolyte during sintering can be from 15% to 30%. Larger electrolyte plates require better accuracy in shrinkage values to maintain the tolerances required for device manufacturing, especially with multi-cell devices. For example, an electrolyte with a length of 50 cm and through-hole positioning tolerances (ie record repeatability) of +/- 200 μηι in the sintered state is expected to shrink the electrolyte by more than 0.05%. . Laser micro-machining of the through-holes 102 in the sintered electrolyte plate 100, however, eliminates the need to accurately predict shrinkage of the electrolyte during sintering, as no electrolyte distortion will occur after sintering. through-hole patterns.

Practical mechanical drilling of 20-pass holes limits the diameter of the holes to a minimum of approximately 75 μιη after firing. Although 50 μηι mechanical perforations are known, the lifetime of the mechanical drilling at these diameters is very short. Laser micro-machining of through holes 102 allows for a practical reduction in hole diameter (less than 75 μηι) as well as the manufacture of absolute hole patterns. For example, a pattern of several smaller through holes arranged in clusters may occupy a through hole of 75 μηι in diameter. Smaller bore bore diameters allow for more effective filling of the bore. Micro machining 5 also enables the creation of through holes 102 at optimal times in the manufacturing process. Holes can even be formed into various layers of material attached to the electrolyte plate. For example, the holes may be micro-machined after the anode layer 103 located on the zirconia-based electrolyte ion plate 100 has been printed and burned, which creates a continuous passage hole through both layers (the electrolyte plate 100 and anode 103) simultaneously. Figures 2a, 2b, respectively, schematically illustrate examples of through-holes 102 drilled through electrolyte plate 100 and anode / electrolyte plate layers 100,103. Different cross-sectional geometries of through-holes (eg non-circular) are also achievable by this method.

By comparison, mechanical drilling via 20 holes with diameters of less than 75 μιη has reduced equipment life due to drilling breakage. Through-holes with a diameter of less than 75 μιη with an aspect ratio (L / D) of length (electrolyte thickness to hole diameter of approximately 1: 1 (ie 25 0.3: 1 to 2: 1) will have more efficient filling as well as better durability.The smaller through holes 102 filled with the conductive material would have fewer gaps and defects and therefore extended mechanical durability.The larger through holes (larger than 75 μιη, and especially larger than 100 μηι in diameter) are more likely to form gaps in sintering path filling, while the smaller path provides a higher surface to path volume ratio, counteracting this tendency. 102 on sintered electrolyte plates 100 improves the quality of the filling and sintering of the conductive pathway filling material. It is possible that the through-holes 102 have a diameter of less than 75 microns, and more preferably less than 50 microns, with an L / D aspect ratio of 0.3: 1 to 1: 5, and even more preferably 0, 3: 1 to 1: 1. Through holes with diameters smaller than microns and aspect ratios of 1: 1.25 are more preferred. Drilling small through holes with preferred aspect ratios is advantageously made possible by the micro-machining method described above in accordance with the present invention.

With the small through-hole diameters, it may be advantageous to increase the number of through-holes to maintain the resistance of the current path through the tracks. Reducing the diameter of through holes 25 from 75 μιη to 50 μιη implies a reduction in cross section of approximately 66%. The cross section reduction is defined as 1- (track area 50 µm in diameter) / (track area 75 µm in diameter). In this case, the number of lanes can be increased by a factor of 2 to 2.5 to compensate for the reduction in area (cross section). However, in many cases, an increase in the number of lanes is not necessary as the resistance of the lanes is not a limiting factor. In the case of tracks with diameters smaller than 50 μηι, it may be preferred that smaller track groupings or groups are used to replace a single large track. For example, nine 25 μιη boreholes have the same cross-sectional area as a 75 μηι borehole and could effectively replace this single pathway. These small through-holes can be grouped in a variety of shapes, including linear through-hole arrangements, circular or rectangular grouping (s) from through-holes 15, or any pattern that provides good integrity. mechanics and proper current distribution.

Multiple Device Fabrication: Since mechanical cutting of sintered electrolyte would cause uncontrolled cracking and drastically reduce resistance due to defects created, mechanical cutting is generally performed on green (ie, non-sintered) electrolytes. However, since mechanical cutting requires that the electrolyte plates be cut to size in the unburnt state, only one fuel cell device 25 can be fabricated by substrate. The ability to laser cut or ablate the sintered electrolyte plate at absolute times during fuel cell device fabrication allows more than one fuel cell device 150 to be fabricated on a single oversized electrolyte plate substrate 100 (See Figure 3). Once the 5 fuel cell devices are complete, they can be cut using only laser micro machining, and thus separated from each other. This approach can be used to fabricate multiple fuel cell devices in parallel to increase manufacturing throughput. If an oversized electrolyte plate is used, the fuel cell device defaults can also be changed as necessary to avoid defects in the electrolyte plate 101 and further increase performance. Figure 3 schematically illustrates the concept of fabricating multiple fuel cell devices into a single common electrolyte plate and separating them (via laser cutting) after the last print / burn step. The exemplary laser cutting path (ablation path) is schematically illustrated by an arrow 2 around one of the 20 devices. The laser ablation path is to create a new edge surface as the fuel cell device is being cut. Thus, laser micro-machining allows fuel cell devices to be cut from electrolyte at absolute times during the manufacturing process. Fabricating multiple fuel cell devices on a single electrolyte plate 100 reduces the number of manipulation steps by a factor equal to the number of fuel cell devices printed simultaneously. Thus, while a fuel cell device can be printed at one time on a single electrolyte plate, it is preferred that two or more fuel cell devices 150 be printed on a single sintered electrolyte plate 100 and that complete fuel cell devices 150 are laser cut apart from each other after manufacture. That is, the anodes and cathodes and other layers (if required) are printed on a sintered electrolyte plate 100, the through holes are drilled and filled, and the electrolyte plate 100 supporting the various fuel cell devices printed by the electrolyte. less partially is then burned (sintered). After sintering, 15 the electrolyte plate 100 is laser micro-machined to cut complete or partially complete fuel cell devices 150. For small fuel cell devices, 10, 20 or more may be printed on a single plate. 100 electrolyte measuring 30 cm or more in width or 20 height. It is noted that fuel cell devices 150 may be identical or of different construction. For example, fuel cell devices 150 situated on a single sintered electrolyte plate 100 may be multiple cell devices, single cell devices, or a combination of both. Such fuel cell devices may be of the same or different sizes and may have the same aspect ratio or different aspect ratios (width / length).

Fabricating multiple devices 150 on a single electrolyte plate 100 minimizes unwanted edge creases, 5 undulations, and thickness variations, as these problems occur primarily at the edges of the electrolyte plate, and in the middle of the devices. In addition, it minimizes the handling frequency of the device (s) and the amount of time each device is manipulated, which leads to increased throughput.

Minimization of ripples and / or creases on the edges of the electrolyte plate: Laser micromachining enables the electrolyte plate to be oversized in the raw state and to be cut to size after sintering. If any crease or edge curl occurs while the electrolyte plate is sintered, creases and / or folds may be removed by laser cutting after sintering. Removing material after sintering the electrolyte plate eliminates any need for stacking the electrolyte plates 20 or applying weight to the electrolyte plates during sintering as a way to reduce edge curl. 1 mm to 5 mm outer region of the electrolyte plate is removed after sintering to reduce or eliminate this edge curl. Thinning about 1 mm 25 from the edge of the electrolyte plate significantly reduces edge creases and ripples and considerably improves edge surface quality, such as roughness along the edge face and the likelihood of an edge cracking, break or other bulge that would concentrate tension. While it is preferred that the minimum possible amount of material be removed, a larger part of the perimeter may be removed, for example 3 cm or more if necessary.

Reduction in Electrolyte Plate Edges: Another benefit of using laser micro-machining when cutting fully fabricated 150 devices from an oversized electrolyte plate substrate is the possible reduction of the electrolyte plate B edge around the printed electrodes. 152 (see Figure 4). Printing a particular electrode pattern (or setting the electrode pattern in general) requires a minimum electrolyte size larger than this pattern. The smaller the electrolyte plate, the harder it is to precisely align and print well-defined details on or near the edge of the electrolyte plate. Using laser micromachining, all electrode layers can be printed / burnt, and then the final edge of the device can be cut arbitrarily close to (or through) the printed fuel cell electrodes. For example, the resulting electrolyte plate may have an unprinted edge that is less than 5 mm, or less than 3 mm, or even less than 2 mm wide. Reducing the electrolyte plate edges allows new fuel cell device designs that were previously not possible with the electrodes present to the edge of the electrolyte plate. In addition, this creates less inactive area on the electrolyte plate. The chopped device 150 may even have an electrolyte plate 100 that has been micro-machined / laser chopped so that it has no unprinted edges.

Laser micro-machining can be used to cut or thin fuel cell devices after the final electrode, track filler or conductor bar has been deposited and sintered. This allows fuel cell devices to be manufactured with much less unprinted (inactive) electrolyte edge along the edges than is usually practical for printing or manipulation. For example, laser perimeter cutting of fuel cell devices after the final manufacturing step allows for much greater surface utilization of the electrolyte plate. On the electrolyte surface, a larger area can be covered with functional electrodes and contacts if laser cutting / micro-machining is used. Similarly, printed electrode patterns or other additional layers may be formed across the electrolyte edge without regard to manipulation during processing. Typically, in fuel cell devices, only a small portion of the area near the edge may be printed with electrodes or other components due to the difficulties encountered in holding and manipulating the fuel cell device. The method of the present invention allows the electrodes, conductor bars, conductors or other device components to cover 5% to 100% (Figure 4) of the perimeter of the electrolyte plate 100 to a distance B less than 5 mm from the plate edge. electrolyte, or even to the very edge.

Laser cutting the edges of fuel cell devices allows additional details to occupy a much larger part of the device perimeter and allows them to be much closer to the electrolyte edge than when using other cutting methods. In the case of laser cutting, any additional electrolyte required for manipulation or processing purposes may be removed by cutting after the fabrication of the device is complete.

Laser cutting / micro-machining allows the final dimension of the fuel cell device to be created after mounting the fuel cell device 150 on or next to a frame or distributor frame, or a set of multiple fuel cell devices. . For example, the electrolyte or fuel cell device may be laser micro-machined after it has already been mounted on a frame. This allows a larger device to be driven during the process for handling purposes, including mounting, and then roughened later to remove excess. Accordingly, according to some embodiments of the present invention, the laser micro-machining method according to the present invention would be used after mounting a larger than necessary fuel cell device on a frame or assembly of several laser cutting or chopping this larger fuel cell device after mounting it to the desired final dimension.

Surface Pattern Machining: 5 laser micromachining can be used to perform surface pattern machining. Surface machining of electrolyte plates and / or fuel cell devices includes texturing, corrugation and micro-windowing. Micro-windowing is the process of creating very thin regions on the surface of the electrolyte. For example, surface patterns 105, such as microwindows 105 ', may be laser micro-machined on the sintered electrolyte plate 102 opposite previously printed electrodes (anodes, cathodes) or other layers of fuel cell devices 150. Thus, it is possible to create thinner electrolyte plate windows than would be possible with molding techniques because molding / bonding techniques require a minimum electrolyte thickness on the unburned (ie gross) electrolyte plate to survive the release of the electrolyte plate. raw plate from the holder on which it is cast. Cathodes or other layers may then be printed on the laser micro-machined areas so that the windows are still sandwiched between the anode-cathode pairs or between other printed layers (such as, for example, conductive bars or catalyst layers). One embodiment of

Surface micromachining / patterning is described, for example, in the embodiment of Example 9 and is illustrated in Figures 26a to 26C and 27a to 27d.

Laser cutting of the final electrolyte shape after fabrication is complete allows quality control test structures to be fabricated in parallel on each electrolyte plate 100. (For example, small test devices may be fabricated on each electrolyte plate. near the actual 150 fuel cell devices.These small test devices will go through the same steps and conditions of manufacture as the actual fuel cell device.When manufacturing is complete, these small test devices (witness samples) can be This allows for destructive and non-destructive testing of device performance to take place in these small test quality control samples rather than sacrificing a real fuel cell device. After fabrication, these structures can be removed by cutting for destructive testing or other testing. would require actual devices to be sacrificed for testing or serial fabrication of separate test devices.

Examples using laser configuration # 1 (Example la, lb)

In this configuration of the laser micro-machining system (See Fig. 5), the quadrupled frequency Nd-YAG ns 160 laser from Lambda Physik Starline, GmbH, having an output wavelength of 266 nm at a rate of 1 kHz repetition, and a maximum pulse energy of 2 mJ to micro-pass through holes in a 100 ceramic electrolyte plate. Several Mi mirrors direct the laser beam to an L1 optical focusing lens. The sintered electrolyte plate 100 was supported by a mobile XY stage Si, and the Lj lenses directed the focused laser beam to the electrolyte plate 100. The pulse duration of laser 160 was 10 ns. Straight edges, through holes and curved patterns were micro-machined on the 20 μιη sintered 100-electrolyte plate. The electrolyte plate had a composition and thickness substantially similar to those described in US patent application 2004/0265663. The depth of focus of the laser beam was about 300 μηι. Note that a ps or fs laser system can also be used (providing similar or different absorption wavelengths). In addition, it is possible to use systems that create focus depths ranging from 1 μηι to 1 mm, whatever the specific laser system. These lens systems allow you to control the size of the point, and thus the size of the micro-detail. In addition, they allow laser micro-machining of electrolyte plates with surface height variations (eg, corrugated or patterned surfaces). During laser micro-machining of such electrolyte plates, the height of corrugations or surface variations must be equal to or less than the depth of focus. Example Ia A flat-convex (PCX) Li lens with a focal length of 10 cm was used to focus light in close proximity to the zirconia-based electrolyte plate. A simple percussion drilling technique was used. The 266 nm 160 laser had its optical power level set at 340 mW. This power level corresponds to 340 μΐ per pulse. Since the through-hole diameter of this example is approximately 50 μιη, this gives us a level of

The

Laser fluency of about 17 J / cm. In the experiment, the hole was laser cut / drilled through the electrolyte plate after less than 2000 pulses or 2 seconds. The minimum creep level required to observe laser ablation effects (ie ablation threshold level) was less than 6 J / cm, for example about 1 (0.9 to 1.1 J / cm). The shape of the passageway produced is influenced by the shape of the laser beam. Laser micromachining without generation of cracks was also achieved using a range of power levels from 100 to 600 μJ per pulse, and creep levels from 5 to 30 J / cm.

Figure 6a and Figure 6b are photographs taken by an optical microscope of the exemplary micro-machined through holes. Both the upper surface of the electrolyte plate (ie, the laser-focused side in Figure 6a) as well as the lower surface of the electrolyte plate (ie, the laser-emitting surface in Figure 6b) are shown. The redeposition of material that was ablated from the generated plasma was observed in the electrolyte plate in the form of ring patterns 108, but it was observed that the redeposition may be reduced, for example, by using ultra short pulsed lasers (<100 os), by heating the electrolyte plate 100 to elevated temperatures, or by using a purge gas or waste collection chamber. Figure 6a and Figure 6b illustrate that although the redeposited region is present (in the form of ring structures around the laser micro-machined through holes), there is no observable microfissure. The mechanical integrity of the cut edges was observed in accelerated aging by exposing the water vapor micro-machined holes at 105 ° C-108 ° C and 3.5-6.5 psi for about 115 hours. No accelerated transition to the monoclinic structure at the cut edges was observed compared to the loose material.

Example Ib

Figures 7a and 7b are SEM images of borders

laser-machined straight lines with the laser cutting equipment described above and the same configurations using a cutting speed of 1 mm / s. Cutting speeds of 0.5 to 2 mm / s may be used, but the cutting speed was ultimately limited to the laser repetition rate (ie the maximum speed is less than the point size diameter x repetition rate). More specifically, Figure 7a shows a top view of the surface of the laser microstrained edge and Figure 7b shows a side view of the surface of the microssinated edge. Redeposition 108 is seen as a discolored strip near the micro-machined edge on the laser side (see Figure 7a).

Examples Using Laser Configuration # 2 (Example 2 to 4F)

In another embodiment of a system of

laser micromachining for laser cutting (nanosecond) of the sintered zirconia-based electrolyte plate, a quadruplicated frequency NdiYVO4 laser produced by Spectra-Physics (HIPPO-266QW) (Examples 2 to 3B) was used. The output wavelength of this exemplary laser is 266 nm. The ns 160 laser, operating at a repetition rate of 30 to 120 kHz, has a peak laser power of approximately 2.5 W and a pulse duration of less than 15 ns according to the manufacturer's specifications. A 3X optical beam expander (BE) and a 10.3 cm Li focal length telecentric lens were used in conjunction with the laser 160 to cut the electrolyte plate 100 (Figure 8). Single pulse ablation in the electrolyte test samples showed that the focal point size of the laser beam (beam waist) is about 20 μιη in diameter.

Example 2

With an optical laser power of 1.7 W, polarized light parallel to the cutting direction, and a repetition rate of 30 kHz, a speed of 40 mm / s was obtained with good reproducibility. The creep level was calculated to be approximately 18 J / cm2. SEM images of the electrolyte plate edges (266 nm nanosecond laser cut) of the electrolyte plate of this exemplary embodiment are shown in Figures 9a to 9c. Figure 9a illustrates a cross-sectional view of a laser cut edge. Note that the laser caused ablation of the top area and the bottom fracture surface. Figure 9b illustrates the edge profile of a laser cut edge (away from the figure). Figure 9c is similar to Figure 9a, but shows a larger magnification of a laser cut edge cross section. It also illustrates the effects of individual laser pulses on the upper ablation region.

The SEM images in Figures 9a to 9c show that, under the conditions used in this example, approximately 7 μιη of zirconia material was removed by the laser ablation process (ablation region 110 of Figures 9a to 9c) prior to the remaining electrolyte material. zirconia have been self-fractured by thermal stress (fractured region 112). The tensile thermal stress was generated by the temperature difference between the upper and lower surfaces of the sintered ceramic electrolyte plate. This is in stark contrast to the femtosecond laser cutting process, where cutting is achieved by ablating all materials and having a negligible thermal effect. Laser micro-machining (Examples 2-4) produces a self-cleaving or self-breaking effect that increases cutting speed. Edge cutting demonstrations were performed with the ns laser with repetition rates of 30 to 50 kHz and sample stage translation speeds of 25 to 40 mm / s. At 30 kHz, according to some embodiments, the average laser power incident on the electrolyte plate was 1.7 W, and at 50 kHz the average laser power incident on the electrolyte plate was 5 1.5 W Other methods of defined-detail laser micro-machining and stress-cutting by fracturing electrolyte plates are also possible. For example, fs and other laser systems, system parameters, and applied external forces may also be used. Figures 9a to 9c illustrate features of

morphology of sintered and laser cut edges. The laser ablated portion forms the edge level (region 110) illustrated in Figure 9b. Nanosecond laser ablation of the electrolyte is accompanied by local fusion (zone or region 114) 15 with larger crystals, as shown in Figure 9c. In Figure 9c, the individual pulse strokes 116 are clearly visible. The fractured part of the material (region 112) has a granular nature. The self-fracturing process is caused by the thermal stress generated by the absorption of laser light into the material.

Example 3A

We also examined the roughness of the edge surface obtained as a function of the cutting technique. In addition to differences in edge shape depending on the cutting method as described in Example 2, there are also differences in edge face roughness. To observe these differences, edges cut under varying conditions were evaluated using an optical interferometer. The roughness of each edge face was measured over an area of 0.09 mm x 0.01 mm. These areas were selected to avoid the beveled corner (region 110) similar to that described in Example 2 and shown in Figures 9a through 9c which would otherwise have resulted in lost counter-reflected data. The edge faces created by laser micromachining of the fs-sintered electrolyte (described below as an alternate laser configuration) and the ns laser (described in Example 2) were evaluated. In addition, the edges created by mechanical cutting and CO2 laser cutting of the non-sintered electrolyte were evaluated after being sintered. All data points presented are values averaged over 4 measurements from the same edge face.

Figures 10a to 10c show the peak-valley roughness, rms and Ra values for the ns (266 nm) laser cut edge surface as a function of the cutting speed. These figures illustrate that faster cutting processes result in less roughness on the edge surface. By adjusting the cutting speed, roughness values less than 5.5 μηι (peak-valley), less than 0.4 μηι (rms) and less than 0.3 μηι (Ra) can be obtained. Figures 11a to 11c show the edge surface roughness values obtained in laser cut samples fs. Figures Ila through Ilc show surface roughness data as a function of laser power. Figure 11a shows that peak-valley roughness decreases as laser power decreases. These values are generally larger than the roughness values of the ns laser edge face due to the ablation caused by the fs laser. The self-cleaving or self-breaking process created by laser cutting ns creates a more uniform edge surface than that obtained by mechanical cutting.

For comparison, crude electrolyte plates were cut with (i) CO2 laser (10-6 μιη) and (ii) mechanically with a knife edge, and then sintered. Electrolyte samples cut into the non-sintered and then sintered CO2 laser had average edge surface roughness values as small as: 13.04 ± 1.21 μιη (peak-valley), 2.52 ± 0.17 μιη (rms), and 1.90 ± 0.07 μιη (Ra). Samples that were mechanically cut in the unsintered state and then sintered had mean edge surface roughness values as small as: 5.63 ± 0.79 µm (peak-valley), 0.43 ± 0.18 μιη (rms), and 0.32 ± 0.15 μιη (Ra).

The cutting method described above produces an electrolyte plate with an edge surface having ablation greater than 10% (see, for example, region 110 20 shown in Figures 9a to 9c). Preferably, the edge surface has between 50% and 90% fracture (Figures 9a to 9c, region 112). Fracture area 112 clearly differs from ablation or fusion area 110 (see Figure 9c) in that the fracture surface is straight, relatively flat, and perpendicular to the primary surface of the electrolyte plate compared to the surface of the fracture. that has suffered ablation or fusion that is more rounded and not perpendicular to the surface of the electrolyte plate. Less preferred would be an edge showing partial fusion of the electrolyte surface. Also preferred is a device with an edge having less than 20% of circumference 5 exhibiting fracture that deviates more than 100 microns (i.e. less than 20% deviates more than 100 μηι) from the laser ablation path. Deviation from this path is an inaccurate cut and represents an imperfection of the finished electrolyte plate or fuel cell device. The main causes of this deviation are: inadequate laser power, repetition rate or speed.

Example 3B

This example demonstrates laser ablation-related redeposition. Referring to the optical microscope images of Figures 6a and 6b described above, the redeposition area 108 around the laser machined through hole is observed. The through hole was obtained by laser percussion drilling with a 266 nm Nd: YAG laser with a pulse duration of 10 ns and a laser fluency of 17 J / cm described in laser configuration # 1. The characteristics of this redeposition area can be controlled by varying the laser exposure conditions (wavelength, pulse duration, pulse energy, cutting speed, repetition rate), as well as sample temperature and purge gas. and / or vacuum (e.g., its presence or absence, amount of vacuum applied, amount and composition of purge gas) or other parameters. For more information on the redeposition zone, an XPS (X-ray Photoelectron Spectroscopy) analysis was performed. Edges that were mechanically cut in the raw state and then sintered, as well as edges 5 cut with an ns laser after sintering were evaluated. Specifically, the described # 2 laser configuration (quadrupled frequency NdiYVO4 laser, Spectra-Physics HIPPO-266QW) was used to create the laser machined edge at a cutting speed of 35 mm / s. Figures 12a and 12b show the XPS line profile data of the relative concentrations of yttrium and zirconium on the sample surface as a function of edge distance. Figure 12a shows that the zirconium level remains at a relative level of approximately 80% and the yttrium level is at a relative level of approximately 20% within 1200 μιη 15 of the mechanically cut and sintered edge. Figure 12b shows XPS data from the same sample, but from an edge that has been laser machined. This shows that the relative level of zirconium is approximately 90% and the relative level of yttrium is approximately 10% within 200 μιη of the laser machined edge. About 1000 μιη from the laser-machined edge, although these levels carry over to those observed at the mechanically cut edge. The redeposited material observed close to the laser microusinate edge has a higher zirconium-to-yttrium concentration ratio.

Examples 4A-4F The configuration of the laser micro-machining system for cutting and / or drilling holes in the sintered ceramic electrolyte plates 100 used in Example 4A-4F is similar to that of Examples 2, 3A and 3B (shown in Figure 8).

However, the laser micromachining system of Examples 4A to 4F utilizes the triple frequency NdiYVO4 laser 160 with an output wavelength of 355 nm. Such a laser is available, for example, from Coherent, Inc. (e.g., COHERENT AVIA-X). The Examples 4A-4F laser micromachining system also includes a plurality of mirrors Mi that direct the laser beam to a galvo-scanner / f-θ lens. The sweeper / lens f-θ is centered on the Z axis, perpendicular to the XY Si stage. (The sweeper / lens f-θ is indicated as the Li lens, which, in this embodiment, is the Scanlab scanning device. HurryScan 10 with a focal length telecentric lens of 100). During the laser micro-machining process, the sintered electrolyte plate 100 was supported by a mobile XY Si stage, and the lens Lj directed the focused laser beam to the electrolyte plate 20. The electrolyte plate 100 had composition and thickness. substantially similar to those described in US patent application 2004/0265663. The NdiYVO4 160 laser has an M2 value (M2 is the beam quality factor) of less than 1.3 and an output diameter of 3.5 mm. In some experiments, an optional 3X beam expander (BE) was used to expand the laser beam provided by laser 160. The nominal diameter of the 2

beam w / e of the expanded beam was 10.5 mm. In these exemplary embodiments, the inlet opening of the shuttle sweeper is 10 mm, so there is some beam clipping. The focal point size l / e of the laser beam on the 100 electrolyte plate 100 was about 6.1 μηι. Unless otherwise stated, the laser power and hence the energy of the laser pulse is measured on the surface of the electrolyte plate.

More specifically, the sintered zirconia-based thin electrolyte plates 100 were extended over the XY Si stage. The electrolyte plates 100 were produced by sintering and bonding processes of dust, slip and tapes. These processes produce 100 electrolyte plates with one side appearing brighter than the other. The brightest side of the electrolyte plate is the side of the plate that touched the tape bonding support film. Unless otherwise indicated, laser cutting and drilling with the micro-machining system of Examples 4A-4F were performed with laser light incident on the bright side. Optimal focus 20 is achieved by adjusting the distance along the z axis. The cut is obtained by translating the electrolyte material with the XY stage. The drilling of the through holes was performed using the sweeper (ie, moving the focused laser beam relative to the electrolyte plate).

Laser cutting of electrolyte plates

Example 4A: In the laser micromachining system of Example 4a, an optional 3X beam expander was used to expand the laser beam provided by the NdiYVO4 160 laser. In this exemplary embodiment, the 5-pulse energy of the laser beam was 102 μJ and the laser pulse repetition rate was 50 kHz. The incident laser power on the electrolyte plates was 5.1 W. The laser beam was linearly polarized with the polarization vector at about 75 ° from the cutting direction. A cutting speed of 160 mm / s was obtained with the orderly separation of the electrolyte plate parts. The laser creep level in the sintered (ceramic) electrolyte material was about 350 J / cm2. This level of creep is above the laser ablation threshold at the wavelength of 355 nm. A total of 21 electrolyte plate samples with a dimension of 2 cm χ 8 cm were prepared by cutting the sintered electrolyte plates with the laser micromachining system of Example 4A and subsequently the resistance was tested using the 2-inch bending method. points. The test results are described later in this report.

Example 4B: In the micro-machining system the

Example 4B, an optional 3X beam expander was used to expand the laser beam provided by the NdiYVO4 160 laser. In this exemplary embodiment, the laser energy of the laser beam was 95 μJ and the pulse repetition rate 25 was 50 kHz. The incident laser power on the electrolyte plates was 4.8 W. The laser beam was linearly polarized with the polarization vector at about 75 ° from the cutting direction. A cutting speed of 120 mm / s was obtained with the orderly separation of the electrolyte plate parts. The laser creep level on the material was approximately 5 330 J / cm. The creep level is above the laser ablation threshold at the 355 nm wavelength. A total of 29 electrolyte plate samples with a size of 2 cm χ 8 cm were prepared by cutting the sintered electrolyte plates with the Example 4B laser micromachining system and subsequently the resistance was tested using the 2-mm bending method. points. The test results are described later in this report.

Example 4C: In the Example 4C laser micro-machining system, an optional 3X beam expander was used to expand the laser beam provided by the NdiYVO4160 laser. In this exemplary embodiment, the laser beam pulse energy was 21 μJ and the pulse repetition rate was 125 kHz. Thus, the pulse energy in this embodiment is about 5 times lower and the pulse replenishment rate was about 2.5 times higher than that of Examples 4A and 4B. The incident laser power on the sintered electrolyte plates was 2.6 W. The laser beam was circularly polarized using a quarter wave plate. A cutting speed of 100 mm / s was obtained with the orderly separation of the electrolyte plate parts. The creep level of laser light on electrolyte plate material

2 r A · f

sintered was about 73 J / cm. The creep level is above the laser ablation threshold at the 355 nm wavelength. A total of 17 electrolyte plate samples with a size of 2 cm χ 8 cm were prepared by cutting the sintered electrolyte plates with the 5 Example 4C laser micromachining system and subsequently the resistance was tested using the 2 bend method. points. The test results are described later in this report.

Example 4D: The laser micromachining system of Example 4D used a non-expanded 355 nm laser beam to cut electrolyte plates (ie no beam expander is used). In this exemplary embodiment, the diameter of the laser beam in the focusing lens was estimated to be about 4 mm. Laser cutting of the sintered electrolyte plates was performed with laser pulse energy of 194 μJ (on the electrolyte material) and 50 kHz repetition rate. Thus, the pulse energy provided by the laser of Example 4D was greater than that provided by the lasers of Examples 4A-4C. The laser beam was circularly polarized using a quarter wave plate. A cutting speed of 260 mm / s was obtained with the orderly separation of the electrolyte parts. The laser fluency level in the material was estimated to be 108 J / cm. A total of 26 electrolyte plate samples with a size of 2 cm χ 8 cm were prepared by cutting the chosen sintered ones and subsequently the resistance was tested using the 2-point bending method. The test results are described later in this report.

Separately, 20 control samples of 2 cm χ 8 cm electrolyte plate were mechanically cut from the “raw” plate and then sintered. They were also tested using the 2-point curvature method.

Figures 13a to 13c illustrate an edge face of a laser cut surface of the electrolyte plate sample prepared using the Example 4A micro-machining system. Figure 13a shows the cross section of the micro-machined edge face of the laser micro-machined surface. Figure 13b shows the cross-sectional surface of the micro-machined edge face at a higher magnification. Figure 13c illustrates the edge profile of a laser cut edge (away from figure 15). The engraved depth (the depth of the laser cut groove) was about 8 μιη. Figures 13a to 13c illustrate that certain deposition as well as molten material is present along the laser cut edge.

Figure 14a is an XPS profile showing the change in relative concentrations of yttrium and zirconium as a function of the laser cut edge distance produced by the laser micromachining system of Example 4a. The laser cut edge line profiles (Figures 14a) show that the relative ratio of Zr: Y changes from a value of about 92: 8 at the edge to a value of about 80:20 toward the center. of the electrolyte plate sample. In contrast, line profiles as a function of the distance from the mechanically cut edges (Figure 14b) of a control sample (cut in a raw state and then sintered) show only a small amount of change in the Zr: Y ratio, which is about 80:20 along the distance from the edge of the sintered sample.

Figures 15a to 15c show SEM (scanning electron microscope) images of laser cut edges produced by the laser micromachining system of Example 4C. In this example, according to the SEM images, the laser engraving depth was about 13 μιη or about 50% across the thickness of the material. Since the incident laser power was only 2.6 W, the resulting tensile force produced by heating the laser beam was relatively small. Therefore, the electrolyte plate material was etched to a depth greater than that of Examples 4a and 4b to allow the etched electrolyte plate to separate or divide by the controlled fracture technique. In this example, the amount of laser ablation resulted in stress buildup, which in turn resulted in cracks along the electrolyte edge face. 20 These cracks can be detrimental to edge strength, and therefore are not desired. Figure 15b also shows the granular growth G columns (about 3 μιη vertically) that resulted from laser micromachining under these conditions.

Figures 16a-16c illustrate the edge face of a laser cut electrolyte plate part that was produced by the laser micromachining system of Example 4D. The recorded depth (groove produced by the laser beam) was about 6 μηι or about 23% of the total electrolyte plate thickness. Crystal growth has been observed to place less than 0.5 μιη in length at the boundary between the molten layer and the unaffected material. The fractured edge is extremely uniform and no crack formation is observed.

Holders tested the resistance, using the 2-point bending method, of all laser cut electrolyte plate samples produced by the Examples 4A-4D laser micromachining systems. Regarding the surface where the laser hits, the cut samples were tested with this surface where the laser hits under stress and compression with different sample sets. The resulting edge resistance data were plotted via a Weibull Distribution as shown in Figure 17. More specifically, Figure 17 shows edge resistance (Mpa) vs. probability (percentage) of failure. The conditions of the Example 4D laser micromachining system produced the highest strength values and the least probability of failure (measured in%). The resistance data indicated by Cl correspond to the electrolyte plate samples produced by the micro-machining systems of Example 4A; C2 corresponds to the electrolyte plate samples produced by the micro-machining systems of Example 4B; C3 corresponds to the electrolyte plate samples produced by the micro-machining systems of Example 4C; C4 corresponds to the electrolyte plate samples produced by the Example 4D micro-machining systems, and the last two “sintered” data sets correspond to the measurements (bright side under stress and bright side under compression, respectively) of control samples (mechanically cut 5 in the raw state). When the laser cut test samples were tensioned, the laser micromachining system of Example 4D (i.e. the system without the beam expander) had the highest average value of 1390 MPa. The laser micromachining system of Example 4C (with the beam expander in place) produced the lowest average value of 805 MPa. For the edge strength results for the laser cut test samples placed under compression, the electrolyte plate samples cut with the laser micromachining system of Example 4D produced the highest average value of 1698 MPa. Laser-cut test samples produced by the Example 4C (Right Beam Expander) laser micromachining system under compression produced the lowest average value of 790 MPa. The laser micro-machining system of Example 4D is preferred since both the tensile strength and the compressive strength of the laser cut edges produced by these system conditions are relatively high.

The strength of the laser cut samples with the side where the laser under compression (except those cut with the laser micromachining system of Example 4C) was better than with the side where the laser falls under tensile forces. This can be explained by the adverse effects of fusion and the heat affected zone around the laser ablated groove, which acts as a fracture initiator. Placing the bright side of the electrolyte under compressive stresses for electrolyte samples that were mechanically cut in a raw state produced less resistance than placing the bright side under tensile strength. This is due to the fact that edge curl formed during the sintering process on the mechanically cut samples. This edge curl is removed from the laser microplated samples during laser cutting after sintering, so that edge curl does not adversely affect resistance.

Laser drilling of through holes in sintered electrolyte plates Thermal effects need to be controlled and

minimized during drilling the drilling of thin ceramic plates (eg zirconia-based electrolyte plates) to avoid micro-cracks. Preferably, this is done by minimizing the amount of power that hits the material in order to decrease the temporary stress level. The following examples show some of the exemplary conditions that result in the absence of micro cracks around the perimeter of the hole.

Through holes can be drilled into sintered electrolyte plates using a trepanning technique. Thermal effects during the laser drilling process need to be carefully controlled (as described below, for example, by the formation of pulse patterns) to avoid material cracking due to thermal expansion. As such, drilling of through holes is generally performed in multiple passes around the desired profile. Multi-pass drilling techniques are able to reduce the amount of thermal gradient buildup in the drilling process, thereby preventing the formation of micro cracks during the drilling process.

In order to prevent the formation of cracks in the

electrolyte plates, the laser power is preferably reduced. Since laser power is a product of laser pulse energy and laser pulse repetition rate, this could be obtained by reducing pulse energy or laser repetition rate. In addition, the laser beam scan speed needs to be adjusted accordingly, based on thermal diffusion considerations.

Since single-path microcracking requires high-power optical microscopes or 20 SEMs, an alternative technique for evaluating a drilling method is to drill a series of closely spaced holes and to look for cracks between each other. the holes. Figure 18a and Figure 18b are two 4-hole optical images of 60 µm in diameter, 250 µm apart. 25 180 æl laser pulse energy was used and approximately 25 passes were required to pierce through the material. Initially, at a laser repetition rate greater than about 3 KHz and sweep rate greater than 60 mm / s, cracks were observed along the holes. Figure 18a is an optical image of the holes and cracks advancing along the direction of the holes. The conditions used were: a 4 kHz laser repetition rate, a scan speed of 80 mm / s. As the laser repetition rate and scanning speed is reduced, no cracking occurs along the through-hole chain. This is illustrated in Figure 18b. The conditions were: a 3 kHz laser repetition rate, a scan speed of 60 mm / s. Additional SEM imaging analysis of the individual holes also showed no observable radial cracks along the perimeter of the holes.

The above operation example uses a rate of

low repetition to reduce thermal effects. In Figure 18c, an example is shown using low laser pulse energy. This shows an optical image of the through holes drilled under 21 µJ conditions, a laser repeat rate of 15.04 kHz, and a sweep speed of 600 mm / s. A total of 40 passes were made to drill through the material.

In order to get holes with uniform edges, it is important to consider how the wrists overlap between different passes. This is important when the diameter of the through hole is considerably larger than the diameter of the laser beam in focus. In the following example, pulse patterns from a 60 μm bore hole drilled with the multi-pass trepanning technique are analyzed. Experimentally, it has been found that at a speed of 60 mm / s and a laser repetition rate of approximately 35 kHz, it takes approximately 25 passes to pierce through the electrolyte material. The number of pulses per pass is approximately 10. In Figure 19, pulse patterns as a function of the number of pulses per pass are illustrated. The pulse numbers per pass are: a) 10 + 0/25; b) 10 + 1/25; c) 10 + 2/25; d) 10 + 3/25; e) 10 + 4/25; and f) 10 + 5/25. Clearly, the patterns shown in Figure 19b and Figure 19e produce uniform edges, as the pulses are evenly spread around the perimeter, while Figure 19a and Figure 19f result in a hole with more uneven edges. In general, knowing the number of passes P, the best perforation pattern with the most uniform edge is obtained when the fractional pulse per pass is i / P, where Pz is not an integer, 0 <i <P (; i / P is a weak that could be reduced or that ie P did not share a common factor). The number of pulses per pass 20 could be optimized by changing the scanning speed or laser repetition rate slightly.

Example 4E: The laser micro-machining system used to drill through holes in this example is the laser micro-machining system of Examples 4A to 4D. A 3x beam expander was used to expand the laser beam. Laser drilling of through holes in sintered solid oxide (zirconia) electrolyte plates was performed with a 355 nm triple frequency NdrYVO4 laser 160 providing 50 μJ pulse energy and a laser repeat rate of 10 kHz. The material creep level of the ceramic electrolyte was estimated to be 174 J / cm. The through holes were drilled by sweeping the laser beam with a sweeping galvo. Multi-pass trepanning with a sweep speed of 100 mm / s was used in this example. Approximately 10 to 20 passes were required to ablate through the sintered electrolyte material with a thickness of about 22 μιη. Figures 20a, 20b are SEM photographs of laser-drilled through holes. Figure 20a is an SEM image of the top view of the through hole, while Figure 20b is a cross-sectional view. Figure 20b also shows an edge L formed of molten ceramic material (zirconia based electrolyte) around the perforated through hole. The height of the edge h is about 6 μηι or 7 μηι. No microcracks were formed at the periphery of the hole. The edge L may be roughened 20 with a laser to a height of less than 5 μιη, preferably less than 3 μιη, more preferably less than 2 μιη.

Through holes in the electrolyte plates are for the purpose of allowing a conductor to connect cathode (s) to anode (s) through the electrolyte plate, thereby conducting current between the electrodes through the electrolyte plate. The formation of the rim around the periphery of the through hole can impede current flow and act as a current constrictor, and would otherwise create defects in the subsequently formed layers of the fuel cell device (s). Therefore, the formation of the rim is undesirable.

Note that bead formation was not observed or bead height was insignificant with holes drilled with 266 nm nanosecond lasers. The reason for the edge formation and significant fusion in this exemplary embodiment may be due to the relatively low photonic energy of 355 nm lasers. Unlike 266 nm photons, which may possibly disrupt the chemical bonds of zirconia material, 355 nm laser ablation is dominated by the mechanism of fusion evaporation and laser heating. If the drilling process results in significant edge formation, it is preferable to use a subsequent laser edge roughing step to minimize edge height.

Example 4F: The laser micro-machining system used to drill through-through wires in this example is the laser micro-machining system of Examples 4A to 4D. The laser micromachining system of this example did not utilize the beam expander, so an unexpanded 355 nm laser beam was used in this embodiment. The laser beam diameter at the focusing lens (L1) was estimated to be 4 mm. The laser beam waist on the electrolyte plate was 25 approximately 20 μιη. The laser pulse energy was 194 μJ and the laser creep on the material was about 108 J / cm. A hole with a certain diameter of 60 μηι was drilled (laser micro-machined) through the sintered electrolyte plate after about 30 passes with a 4 kHz laser repeat rate and a 80 mm / s burr rate. After the edge 5 was roughened with a laser roughing step, trepaning was performed to a diameter of 90 µm around the same central location. The roughing step involved 2 passes at a speed of 80 mm / s with the same laser parameters (same pulse energy and pulse repetition rate). The main difference between the drilling and roughing steps was the laser path diameter (s). The purpose of the roughing step is to slightly roughen the edge formed during trepanning through the hole to a height h, where h is preferably less than 5 μιη, more preferably 15 less than 3 μηι, even more preferably smaller than than 2 μιη, and most preferably, less than 1 μιη.

A series of 5 through-holes with a diameter of 60 μιη were drilled with a center-to-center spacing of 1000 μηι. Again, these 60 20 μηι boreholes also incorporated an edge edge roughing step with a circle of 90 μιη diameter (laser beam waist of about 20 μηι). In addition, a series of 5 through-holes of equal geometry were drilled with a 200 μιη center-to-center spacing with the same 25 roughing step. Finally, a series of 5 through holes with a diameter of 40 μηι was formed, and included a 60 μιη diameter edge bead removal step. These were manufactured with a center-to-center spacing of 200 μηι. Figures 21a, 21b are SEM images of laser-drilled through holes after associated laser roughing. Figure 21a is a top view of the through holes, while Figure 21b is a cross-sectional view of the hole. Note the characteristic swirl pattern shown in Figure 21a, formed by the scanning laser beam. The swirl pattern was caused by repeated heating and evaporation by the fusion pool sweep laser beam formed by the previous sweeps. From Figure 21b, we can see that edge formation has been minimized. Low bore height through-holes, as shown in Figure 21b, are desired for use in solid oxide-based fuel cell applications.

Although a laser roughing technique was used to reduce the edge height in the perforated electrolyte samples of Example 4F, other techniques such as spiral drilling and percussion drilling also showed promising results. In Figure 21c and 21d, we present SEM images of percussion-drilled through-holes with a diameter on the laser side of about 40 μηι and a diameter on the laser output side of about 10 μηι. The height of the edge h was about 5 μηι. Another method 25 is the spiral drilling technique. Figures 21e and 21f show images of SEM holes drilled with spiral drilling technique. The edge height was about 9 μηι, as shown in Figure 21 f. Edge roughing, as discussed above, or other refinement of the process could lead to a decrease in edge height.

Examples using the ps laser setup

(Example 5)

Example 5

A peak-second laser was used to micro-pass through holes in electrolyte plates. The ion laser had a pulse width of 10 ps, a wavelength of 355 nm and a pulse energy of up to 28 μJ at a repetition rate of 100 kHz. The laser was capable of a repetition rate range of 50 kHz to 2 MHz and a maximum power of 4 W. A lens with a focal length of approximately 8 cm was used to focus light near the electrolyte plate. The focal point size was estimated to be approximately 50 μιη. Therefore, the laser fluency at the focal point was approximately 1.4 J / cm. A percussion technique was used to micro-pass through holes in the electrolyte material. Microcracks present at various laser repetition rates and power combinations were observed. Such cracks are not desired in the fuel cell device. No cracks were observed in the examples of UV laser micromachining previously presented with creep greater than 1.5 J / cm, and would not be expected if the ps laser had provided higher creep levels, for example, creep levels similar to those provided by other examples (ns and fs settings).

Examples using fs laser configuration

(Examples 6 to 9)

In this configuration, a system of

fs amplified laser (1W Spectra Physics Spitfire® Pro Ultrafast Ti Amplifier: Sapphire). The laser emits a 1 kHz pulse train at a maximum energy of 1 mJ per pulse. The pulse duration is approximately 40 fs, and laser emission is centered at a wavelength of 800 nm. A flat-convex lens with a focal length of 7.5 cm was used to focus the laser light near the electrolyte plate. Based on the Gaussian laser beam quality M value of 1.4, the wavelength, and a beam size of 715 mm (collimated beam diameter), the beam waist at the focal point was calculated to be 15 μιη. The cut tests were performed below the white light generation limit, which was found to be 35 μ / pulse with this lens system. Other focal length lens systems are also possible, such as 3.5 cm or other options. Laser cutting speeds of 0.5 to 2 mm / s were achieved without detrimental effects, but the cutting speed was basically limited by the laser repetition rate. No micro-cracks were observed at the micro-edge.

Example 6 Micro-machining can be used to reduce or eliminate ripple effects of the electrolyte, including edge ripple that occurs during sintering. In large electrolyte plate parts, for example, larger than 5 cm in width or length, edge curl and other irregularities were observed during the electrolyte sintering process. These effects tend to be more pronounced as the size of the electrolyte increases. Depending on the size of the electrolyte plate, these effects were observed up to 4 cm within the edges of the electrolyte plate. Laser micromachining allows these large electrolyte plate parts to be oversized during the sintering step. Laser micro-machining can then be used to later cut off any excessive edge curl, irregularity, or any other defects that may exist after sintering or fabrication of the device. To demonstrate the ability to improve electrolyte flatness with laser micromachining, the fs laser was used to remove a 2mm width from the edge of the electrolyte plate. The flatness 20 of the edge of a sintered electrolyte plate was measured before and after micro-machining. Figure 22 shows surface contours as measured by an approximately 20 μηι electrolyte plate laser profilometer before (top graph) and after (bottom graph) micro-machining, ie after laser cutting / removing a 2 mm wide perimeter of the edge of the electrolyte plate. The electrolyte edge after sintering has a maximum measured height variation of 80 µm, and the electrolyte edge has a much lower measured maximum height variation of 40 μιη after laser micro-machining.

Example 7

To demonstrate laser micro-machining of

In solid oxide-based fuel cell devices (SOFC devices) 150, the edges and through-holes were micro-machined on a sintered electrolyte plate 100 for both 10-cell and 1-cell devices. Both types of fuel cell devices required several rows of through holes to interconnect the electrodes created on either side of the electrolyte. Four different device manufacturing situations have been demonstrated and are shown below:

1. Drilling the holes in plate

bare sintered electrolyte, roughened. The bare electrolyte plate was received, being mechanically cut and sintered (the electrolyte plate was at least one dimension larger than the 10 cm dimension that was required for a 10 20 cell device). Accurate alignment of the edges with the through holes as they were drilled was required. Thus, while eleven rows of passage holes were laser micro-machined on the electrolyte plate using a laser trepanning technique (an example of such a hole is shown in Fig. 25 23a, 23b), its placement was precisely referenced to the edges. of electrically cut electrolyte plate as formed. For trepanning, the laser beam was kept stationary and the sintered electrolyte plate 100 was moved along a circular path. The geometry of the through holes (circular) was similar to that illustrated in Figures 23a and 23b.

The cutting speed was limited by the low repetition rate of the laser source. Based on Figure 23a and Figure 23b, we can see that the quality of the through hole 102 is excellent. Some annular cracks 118 remained in the rear side of the through hole 102 presumably due to the

Λ

shockwaves generated during the laser ablation process. At a higher average power of about 35 mW, annular cracks can be eliminated. With a cutting speed of 0.5 mm / s, the 60 μιη bore holes 102 diameter were laser cut in generally 2 passes with an energy of 30 μ J / pulse and 15 a creep level of 17 J / cm. Fabrication of the 10-cell device was then completed, including the steps of forming the anode, cathode, current collector, through conductors, and busbar structures.

The specific sample shown in Figures 20 23a and 23b was micro-cast using the fs laser but with a pulse energy of 7 μΙ / pulse and a creep level of 4 J / cm. In contrast, the 10-cell and 1 real-cell 150 devices previously described had laser micro-machined through holes using the same fs laser but at 30 μJ / pulse and a level of

__

creep 17 J / cm. These higher pulse energies and creep levels reduced annular crack formation and only 2 passes were required to machine a through hole with the same circular geometry. Although they were micro cracks

Λ

when the fs laser creep was 4 J / cm, the previous near-visible infrared laser micromachining examples presented with creep greater than 4 J / cm2 showed no observable microfissures.

2. Laser roughing and drilling of holes in oversized sintered electrolyte plates We received a bare sintered electrolyte plate that was sized larger than needed for a cell device. In one embodiment, the electrolyte plate dimensions were 12 cm x 15 cm. Both 11 rows of through holes and the perimeter of the device were laser micro-machined using an 800 nm laser. Since the electrolyte plate was oversized, no precise alignment was required for the edges thus formed. Therefore, only overall alignment was required. Approximately 1 cm to 1.5 cm was removed (micro-machined) from the edges of the electrolyte plate during precision laser perimeter cutting, and the through-holes were precisely aligned to the cut / micro-machined edges of the perimeter. Figure 24a shows SEM images of the edges that were cut mechanically in the raw state and then sintered, and images of edges that were sintered and then cut with the femtosecond laser (see Figure 24b). The quality of the produced edge surfaces was similar to that shown in Figure 24b. Figure 24a shows for comparison a cross section of the mechanically cut sintered electrolyte plate (while in the raw state). Measurements of the overall length and width dimensions of the laser micro-electrolyte electrolyte showed a sample-to-sample variation limited by measurement error of less than ± 0.04%. Fabrication of the 10-cell device was then completed, including the steps of forming the anode, cathode, current collector, through conductors, and busbar structures. In a prediction example, the 30 cm long electrolyte is produced with through holes having a track-to-track register error of less than 50 microns. This example demonstrates the edge profile and morphological characteristics of sintered and laser cut edges. Sintered laser machined edges, such as those illustrated in Figure 24b, have an RMS roughness of about 0.4 to 0.8 μιη. In the case of femtosecond laser cutting of the electrolytes, the observed thermal effects were so small that the electrolyte could be cut (perforated) without cracking. Recrystallization of the vaporized and molten material results in the growth of crystalline granules, similar to that illustrated in Figure 24b. The size of the

_>

crystalline granules is smaller than 1 μιη (Figure 24b). At the same cutting speed, increased laser creep will result in the growth of crystalline granule size.

3. Multi-device laser hole drilling in a sintered oversized electrolyte plate substrate, with subsequent cutting and separation of the perforated electrolyte plates corresponding to these devices A large bare electrolyte plate size> 10 cm was mechanically cut and sintered . Multiple groups of 2 rows of 5-pass holes, each corresponding to a 1-cell device, were drilled / laser micro-machined on the large electrolyte plate and multiple sections of the electrolyte plate, each corresponding to a different 1-cell device. , <5 cm in size, were laser micro-machined out of the large electrolyte plate. Thus, the 2 rows of through holes and the electrolyte plate perimeters corresponding to each fuel device were laser micro-machined, and the micro-machined pathways and edges were precisely aligned with each other. Fabrication of the 1-cell device was then completed on each separate electrolyte plate, including the steps of forming anode, cathode, current collector, through conductors, and busbar structures.

4. Fabrication of Multiple Devices on a Single Oversized Electrolyte Plate A large electrolyte plate has been cut.

mechanically and then sintered. This electrolyte plate had at least a dimension larger than 10 cm. Various anode patterns for a multiplicity of 1-cell devices were preprinted and sintered on a surface of the received electrolyte plate. Micro machining of the sintered electrolyte plate was used to drill multiple sets of two rows of through holes 102 (each set corresponding to a different fuel cell device) and the perimeters of the 1 cell devices (<5 cm in size). The micro laser machined details were precisely aligned with the previously fabricated anode layers. The resulting laser cut electrolyte plates (corresponding to 1-cell devices) incorporated both the previously fabricated anode pattern and an aligned through-hole pattern. Fabrication of the 1-cell device was then completed, including the steps of forming the cathode, current collector, through conductors, and busbar structures.

The following is an exemplary process for manufacturing multiple solid oxide-based fuel cell devices on a single oversized zirconium-based electrolyte plate:

The. Sinter a raw electrolyte plate (

(~ 1450 ° C);

B. Print anodes and other layers as needed and sinter (T ~ 1350 ° C);

ç. Laser drill through holes;

d. Fill the through-holes with conductive track material and sinter (T ~ 1250 ° C);

and. Print other layers (eg cathodes), and sinter (T ~ 1200 ° C); f. Print pickup bars, etc., and sinter

(T-750-1000 ° C);

g. Cut each fuel cell device (at least partially completed) by

laser micromachining after the last sintering step.

Note that manufacturing begins with higher sintering temperatures and proceeds to progressively lower sintering temperatures.

Example 8

The edge resistance of the electrolyte based on

Zirconia is of great importance in some applications. To demonstrate the resistance obtained by laser micro-machined edges, 2-point bend tests between parallel plates were performed with approximately 2 cm x 15 8 cm electrolyte samples. The resistance of mechanically cut and sintered samples was measured as a reference. The mechanically cut samples were measured with the most uniform surface that was molded against the Teflon support experiencing tensile strength. Samples with micro-fined edges were tested with the laser incidence side in both tensile and compressive stress configuration. Figure 25 illustrates the strength of laser cut edges (micro-machined) compared to mechanically cut edges. More specifically, Figure 25 shows Weibull distribution probability graphs 25 of the measured curvature resistance. Under a set of conditions, both the laser incident incidence side and stress configurations exhibit resistance distributions similar to the mechanically cut and sintered electrolyte. However, a second set of samples that experienced an increased vacuum force 5 during micro-machining had much higher strength when the laser incident side was under compression. These higher strength samples had a vacuum channel retaining the electrolyte in position during cutting. The vacuum channel (see Figure 8) was aligned on the ion side of the electrolyte opposite the incident laser energy, and the vacuum force was pushing the electrolyte away from the incident laser energy. An unexpected result is that the electrolyte plate cut with the fs laser under these conditions may have greater strength than any of the other 15 mechanically cut or laser cut samples, larger than 2 GPa, 2.7 GPa, and even 3 GPa, compared to the typical resistance of approximately 1.0 to 1.5 GPa. The highest strength parts were cut while a vacuum was applied to the electrolyte plate 100 via vacuum channel (s) 165 20 during the process. cutting by pushing the electrolyte plate 100 down away from the laser during cutting.

A general observation of the femtosecond laser micro-specimens is that the residues around the micro-machined area were significantly smaller compared to the nanosecond laser micro-specimens. The femtosecond laser machined parts exhibit a single surface morphology that exhibits essentially complete ablation without substantial fracture and limited granular growth (eg, the 3YZ electrode bead size was less than 2 μιη, and typically less than 1 μιη ).

The exceptionally high strength of the edges of the electrolyte plate is assumed to be associated with this unique morphology. An electrolyte plate with a laser micro-edge edge surface exhibiting 100% ablation and / or granule size of more than 0.2 microns but less than 2 microns is preferred for resistance optimization.

Examples 9a and 9b Standardization of

Surface.

Example 9a. This example demonstrates the use of laser ablation for electrolyte plate surface standardization. Another identified application of electrolyte laser micromachining is to manipulate the zirconia surface to produce rough, textured or micro-windowed patterns. Partially laser machining through the electrolyte plate 100 allows surface machining that may not be possible by molding or gluing techniques. For example, molding or bonding techniques require a minimum electrolyte thickness in the unburned electrolyte to survive its release from the Teflon support. In some applications, it is preferred that the sintered bare electrolyte be of minimum thickness to survive manipulation as a standalone film. For example, an electrolyte with a thickness of about 20 μιη may be laser micro-machined after the electrode layers have been fabricated onto it. Figures 26a to 26c illustrate a 20 μιη thick electrolyte substrate with a burnt 5 μηι anode layer fabricated on one side. As shown, 5 laser micro-machining is used to partially remove the electrolyte layer producing a window thickness (electrolyte plate standards 105) of less than 5 μηι, which generally cannot be produced on a standalone or electrolyte plate. autonomous. In this case, the existing anode layer provides the mechanical strength necessary to survive manipulation. A cathode layer is then fabricated on the opposite side to complete the fuel cell device. The micro-machined details constitute a significant percentage of the area under the electrodes, preferably greater than about 25%, and more preferably greater than about 40%. The patterns may have a relief (depth) greater than 5 μηι, or preferably greater than 30% and more preferably greater than 50% of the electrolyte plate thickness. The method of the present invention is especially applicable for use with electrolyte plates having an overall thickness <100 μιη and preferably <30 μηι, more preferably less than about 20 μιη, although it may be used with much thinner electrolyte plates, of even 3 or 5 μιη. The method described is also applicable to laser cutting, laser drilling and surface machining of the electrolyte plate after the additional layers have been applied. Example 9b. This example also demonstrates the use of laser ablation for electrolyte plate surface standardization. Laser micromachining of the electrolyte surface with the fs laser system was used to create an IOx 10 matrix pattern of 50 μιη wide squares. The spacing between squares was also approximately 50 μιη. Each square was created by scanning the laser energy for a total of offset line scans of 5 μιη each. The focal length of the lens was 35 mm and the laser power was 4 mW. Figures 27a to 27d show optical microscope data as well as optical interferometric data of micro-machined details. Figure 27a shows a section of the 10x10 matrix pattern as seen with an optical microscope. The slight rounding and enlarging of two of the corners of each square is visible. This is due to the laser persistence at these points during the start and stop of each scan cycle. The average depth of squares is 4.0 µm ± 0.1 µm, and the optical interferometer depth image is shown in Figure 27b. Figures 27c and 27d show optical interferometer images at the bottom of each square detail over an area of 0.04 mm χ 0.04 mm. As shown, the laser scan path is observable. The average roughness values for these laser-machined surfaces were 4.88 µm ± 1.22 μηι (peak-valley), 0.35 µm ± 0.04 μηι (rms) and 0.26 µm ± 0.02 µm. (Frog). For comparison, the values for the non-machined surface of the electrolyte are 1.231 µm ± 0.377 μπι (peak-valley), 0.046 µm ± 0.001 μιη (rms), 0.034 µm ± 0.001 μm (Ra).

The inventive method is applicable to fuel cell devices, and specifically to the electrolyte supported multiple cell manufacturing and design process. The method is especially applicable to the manufacture of multi-cell fuel cell devices manufactured on a common electrolyte substrate and interconnected via conductive pathways. Since, according to one aspect of the present invention, laser micro-machining (e.g. hole drilling and electrolyte finishing) is performed after sintering, laser micro-machining is particularly useful for processing large sized devices. greater than 30 cm, where processing of the unburned ceramic would require extremely strict shrinkage control. An advantage of the method of the present invention is the increase in device manufacturing throughput, production speed and performance.

It will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from its essence or scope. Accordingly, it is intended that the present invention encompass the modifications and variations of this invention as long as they are within the scope of the appended claims and their equivalents.

Claims (15)

1. A sintered electrolyte plate, comprising: a body of a thickness not exceeding 45 μιη, and at least one laser-machined detail with at least one edge surface having at least 10% ablation. Electrolyte plate according to claim 1, characterized in that said at least one edge surface has more than 50% fracture and less than 50% ablation. Electrolyte plate according to claim 1, characterized in that said electrolyte plate is based on zirconia and includes a micro-boundary edge, and the relative concentration of zirconium on the micro-boundary edge is higher than in another area that It is located on the surface of the electrolyte plate farthest from the laser micro-edge. Electrolyte plate according to claim 1, characterized in that said electrolyte plate has a laser micro-machined surface and the laser micro-machined surface has a crystal bead size of less than 1 micron. Fuel cell device including the electrolyte plate according to claim 1, and at least one anode and cathode pair, characterized in that said details are through-holes with diameters of less than 75 microns. Fuel cell device according to Claim 5, characterized in that it has a repeatable through-hole registration repeatability of less than +/- 200 microns. Electrolyte according to claim 1, characterized in that it has an edge resistance greater than 1.8 GPa. Electrolyte plate according to claim 1, characterized in that said electrolyte plate is a zirconia-based electrolyte plate with at least one edge surface exhibiting 100% ablation and granular growth on the edge surface. ablated, where the granule size of the ablated edge surface is less than 2 μιη. Method for micro-machining an electrolyte plate, comprising: (i) supporting a sintered electrolyte plate; (ii) microplating said electrolyte plate with a laser, wherein said laser has a wavelength of less than 2 μιη, a fluency of less than 200 Joules / cm2, and a repetition rate (RR) of between 30 Hz and 1 KHz. , pulse duration less than 1 μιη. Method according to claim 1, characterized in that said laser is a 355 nm nanosecond laser. Electrolyte plate micro-machining method according to claim 10, characterized in that said laser has a pulse duration <1 μ5, wavelength <400 nm, and: creep is between 5 Joules / cm and 200 Joules / cm, repetition rate (RR) of at least 1 KHz, and cutting speed> 50 mm / sec. Method of producing multiple fuel cell devices, characterized in that multiple fuel cell devices (i) are manufactured at least partially on a single electrolyte plate; and (ii) are laser cut apart from each other according to the micro machining method of claim 9. Method of micro-machining an electrolyte plate according to claim 9, characterized in that said method includes cutting by micro-machining more than 1 mm from at least one side of the electrolyte plate to remove at least part of the edge irregularity of the electrolyte plate. Electrolyte plate according to Claim 9, characterized in that the micro-machining is performed by ablation in conjunction with self-cleavage. Method for micro-machining an electrolyte plate according to claim 11, characterized in that it includes a laser micro-machining step at least one additional layer situated on said electrolyte plate.